Even golfers using a motorized cart can burn about 1,300 calories and walk 2 miles when playing 18 holes. Halfdark/fstop/Corbis hide caption

itoggle caption Halfdark/fstop/Corbis

Yoga practitioners celebrate the solstice in New York's Times Square in 2011. Richard Drew/AP hide caption

itoggle caption Richard Drew/AP

In a FIT zone at Bell Street Park in East Palo Alto, Calif., friends from the neighborhood now gather regularly to play volleyball. Jeremy Raff/KQED hide caption

itoggle caption Jeremy Raff/KQED

NPR senior Washington editor Beth Donovan walks on a treadmill desk in her office in Washington, D.C. Meredith Rizzo/NPR hide caption

itoggle caption Meredith Rizzo/NPR

Olympic gold medalist Sanya Richards-Ross pulls on compression sleeves before a 400-meter race at the World Indoor Athletics Championships in Istanbul in 2012. Martin Meissner/AP hide caption

itoggle caption Martin Meissner/AP

Greg O'Brien gathers his thoughts before a run in 2013. "Running is essential," he says. Michael Strong/Living With Alzheimers hide caption

itoggle caption Michael Strong/Living With Alzheimers

Coss Marte started selling drugs at age 13 and by 19, he says, he was making $2 million a year. After serving a prison sentence, he founded a "prison style" fitness boot camp. Justin Fennert/Courtesy of Behind the Stache hide caption

itoggle caption Justin Fennert/Courtesy of Behind the Stache

Joyce Powell, 80, attends an exercise class at UT-Arlington with her husband, Thomas (right). Powell says she feels more confident in getting around and traveling since taking the classes. Dane Walters/KERA hide caption

itoggle caption Dane Walters/KERA

Varying speed while walking may make the activity much more effective. iStockphoto hide caption

itoggle caption iStockphoto

TK Leif Parsons for NPR hide caption

itoggle caption Leif Parsons for NPR

Dr. Robert Zarr, second from right, leads a hike through a park in Washington, D.C. Diana Bowen/National Park Service hide caption

itoggle caption Diana Bowen/National Park Service